Results 251 to 260 of about 3,737,177 (309)

Evolution of Organic Aerosols in the Atmosphere

Science, 2009
Framework for Change Organic aerosols make up 20 to 90% of the particulate mass of the troposphere and are important factors in both climate and human heath. However, their sources and removal pathways are very uncertain, and their atmospheric evolution is poorly characterized.
Jimenez, J.L., Canagaratna, M.R., Donahue, N. M., Prevot, N. M., Zhang, Q., Kroll, J. H., DeCarlo, P. F., Allan, J. D., Coe, H., Ng, N. L., Aiken, A. C., Docherty, K. S., Ulbrich, I. M., . Grieshop, A. P., Robinson, A.L., Duplissy, J., Smith, J. D., Wilson, K. R., Lanz, V. A., Hueglin, C., . Sun, Y. L., Tian, J., Laaksonen, A., Raatikainen, T., Rautiainen, J., Vaattovaara, P., Ehn, M., Kulmala, M., Tomlinson, J. M., Collins, D. R., Cubison, M. J., Dunlea, E. J., Hufman, J. A., Onasch, T. B., Alfarra, M. R., W   +70 more
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Evolution of the atmosphere

Proceedings of the Geologists' Association, 1998
Planetary atmospheres depend fundamentally upon their geochemical inventory, temperature and the ability of their gravitational field to retain gases. In the case of Earth and other inner planets, early outgassing released mainly carbon dioxide and water vapour. The secondary veneer of comets and meteorites added further volatiles.
openaire   +2 more sources

The evolution of the prebiotic atmosphere

Origins of Life, 1984
One-dimensional radiative convective and photochemical models are used to estimate the vertical temperature structure and composition of the earth's prebiotic atmosphere. Greatly enhanced CO2 levels (100-1000 times present) are required to keep the mean surface temperature above freezing in the face of decreased solar luminosity during the earth's ...
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Evolution of Atmospheres

Science, 1993
An atmosphere is the dynamic gaseous boundary layer between a planet and space. Many complex interactions affect the composition and time evolution of an atmosphere and control the environment - or climate - at a planet's surface. These include both reactions within the atmosphere as well as exchange of energy, gases, and dust with the planet below and
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Atmospheric constraints on the evolution of metabolism

Origins of Life, 1980
Earth's early history may have been characterized by coevolution of microbial metabolism and atmospheric composition. Metabolic developments affected the composition of the atmosphere and the resultant changes in the atmosphere stimulated the evolution of new metabolic capabilities.
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Life and the Evolution of Earth's Atmosphere

Science, 2002
Harvesting light to produce energy and oxygen (photosynthesis) is the signature of all land plants. This ability was co-opted from a precocious and ancient form of life known as cyanobacteria. Today these bacteria, as well as microscopic algae, supply oxygen to the atmosphere and churn out fixed nitrogen in Earth's vast oceans.
James F, Kasting, Janet L, Siefert
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Evolution of a Nitrogen Atmosphere on Titan

Science, 1978
Photochemical calculations indicate that if NH 3 outgassed from Titan it should have been converted to a dense N 2 atmosphere during the lifetime of the satellite. A crucial step in the process involves a gas phase reaction of N 2 H 4 with H ...
S K, Atreya, T M, Donahue, W R, Kuhn
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Formation and Evolution of Titan’s Atmosphere

Space Science Reviews, 2005
The origin and evolution of Titan’s enigmatic atmosphere is reviewed. Starting with the present-day volatile inventory, the question of what was the original composition on Titan and how a satellite of similar size to other Galilean moons managed to acquire and hold on to the required material is discussed.
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Atmospheric chemistry: the evolution of our atmosphere

Journal of Photochemistry and Photobiology A: Chemistry, 1992
Abstract Earth's atmosphere is a disequilibrium mixture of oxidizable materials in the presence of large amounts of oxygen. The entropy reduction is brought about by living organisms using photochemical energy from the Sun. Almost all the oxygen in the atmosphere is derived from photosynthesis; inorganic photochemistry can produce only 10 −9 of the ...
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THE INFLUENCE OF LIFE ON THE EVOLUTION OF THE ATMOSPHERE

1980
The early history of life on earth may have been characterized by coevolution of microbial metabolism and atmospheric composition. Metabolic developments affected the composition of the atmosphere, and the resulting changes in the atmosphere stimulated the evolution of new metabolic capabilities.
openaire   +2 more sources